Improvement in balance slide-valves



UNITED STATES PATENT OFFICE.

DAVID DORMAN, OF WIE-[EATLAND FURNAGE, OF PENNSYLVANIA, ASSIGNOR TOHIMSELF AND THOMAS JOHNSTON.

IMPROVEMENT IN BALANCE SLIDE-VALVES.

Specification forming part of Letters Patent No. 96,560, dated November9, 1869.

To-all whom it may concern Be it known that I, DAVID DORMAN, ofWheatland Furnace, in the county of Mercer and State of Pennsylvania,have invented certain new and useful Improvements in BalanceSlide-Valves; and I do hereby declare that the following is a full,clear, and exact description thereof, reference being had to theaccompanying drawings, and to the letters of reference marked thereon,which form a part of this specification.

My invention relates to that class of slidevalves whereby thesteam-pressure is removed trom the upper surface ofthe valve,keeping thesame evenly balanced.

In the accompanying drawings, Figure l is alongitudinal section of myinvention; Fig. 2, a top plan of the valve; Fig. 3, a detail planthereof.

Letters of reference denote parts.

The valve is of quadrangular shape, and constructed in two sections, Aand B, the divisional line being at or near the center thereof, thevalve having an opening, B', to facilitate the exhaust. The ends or lapof said valve are perforated with a series of holes, A',ol'anysuitableshape. Packing-stripsG,either in one or more rows, areplaced around either in the base A or cap B, which is grooved to receivethem, said strips O being ot' such construction and shape as will admitof a passage underneath the same, as shown inthe accompan ying drawings.They are of triangular shape, said strips being so relatively arrangedthat they will bear against each other and the end strips form a jointagainst the side strips. The face of said packing-strips G bear againstthe face of the corresponding section of the valve, as the case may be,being acted upon laterally and vertically by the steam contained in theordinary steam-chest, 1t, which steam, passing along the groove orpassage underneath said stripsG, forces upward the same, or downward, asthe case may be, pressing the cap B against the lower portion of theordinary steam-chest lid I), thus preventing a downward pressure ofsteam from acting on the upper surface of the valve. As the lap of thevalve travels over a steam-port steam will pass through the perforationsA' and impingeagainst thesteamchest lid D, thus preventing the upwardpressnre of steam from the cylinder from raising the valve from itsseat, and prevents the ingress of dirt or. grit thereon, and as the topof the valve bears against the steam-chest lid the pressure of steam isrelieved from that point, and, providing the upper part 0f the valvewears, the continual action of steam on the packing-strips O forcesupward the cap B, taking up all lost motion and preventing leakage, thusremoving unnecessary friction and enabling the engine to perform morework, with a saving of fuel.

I am aware that quadra-ngular valves using packing-strips and having abearing against the steam-chest lid have been heretofore constructed;but the packing-strips are located on the upper face of the valve, andin their reciprocating motion they cut grooves in the lid, thusrequiring oftentimes labor to adjust and repair the same. My valvehaving the packing-strips at or near its center and having an evenbearing on its upper face obviates that difficulty.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

The arrangement of a series of packingstrips between the upper and lowerportions of a quadrangular divisional slide-valve, said strips being ofsuch construction and shape as will admit of a passage or steamwayunderneath the same, and being so relatively arran ged that they willform a perfect joint with each other, substantially as described and setforth.

In testimony that I claim the foregoing as my own I affix my signaturein presence of two Witnesses.

DAVID DORMAN.

Witnesses ABNER APPLEGATE, Taos. JOHNSTON.

